Activity: Climate Change Evidence

A question that often arises within the teaching and discussion of climate change is, "How do we know climate change is happening?" Or "How do we know that this isn't a natural and normal warm period?"  Evidence can be gathered about recent temperature and weather changes through modern records of weather.  To examine weather further back in time, however, has required scientists to be more creatively resourceful and think outside the box to find ways to analyze the weather and climate of the distant past.
As the student, beginning with the resources below, and any other reputable sources you may find, to explore how the following things can be used to learn about the weather and climate of the past and present, making sure to describe which can be useful for finding out information about the past, which can be useful for learning about the present, and which can be used for both.

ice cores
sea levels / water cover
ice sheet cover
glacial cover
tree rings
pollen
rock formations
fossils
ocean chemistry
landforms

http://www.bgs.ac.uk/discoveringGeology/climateChange/general/pastClimatesEvidence.html
http://www.societe.org.gg/planetguernsey/download/3_Historical.pdf
http://news.bbc.co.uk/1/shared/spl/hi/guides/457000/457037/html/default.stm
http://know.climateofconcern.org/index.php?option=com_content&task=article&id=71
https://koshland-science-museum.org/explore-the-science/earth-lab/changes#.UjdVMmQfZ69

Source: Nasa Earth Observatory

There are two different types of data presented here, one is direct climate measurement and the other is proxy climate information.  Direct climate measurements are information which are directly related to the state of the climate.  Proxy climate information comes from sources which aren't directly related to climate but information about the climate of the time can be inferred from the data.  Which in the list above give direct climate data and which provide proxy climate evidence?  Explain your reasoning.